The invention concerns a method and a system for analyzing MR spectra. A method for automated interpretation of MR spectra is known from the article “Automated structure verification based on 1H NMR prediction”, Magnetic Resonance in Chemistry, Volume 44 Issue 5, Pages 524-538, 2006.
In the state of the art MR spectra are processed in the peak analyzer which performs a peak picking routine which yields a peak list. The resulting peak list, that typically only contains the chemical shift values of the peaks, is then passed along to the multiplet analyzer which performs a multiplet analysis. The result of the multiplet analysis is a list of multiplets with their chemical shift positions, their multiplicity and their coupling constants. At some point during the analysis the expected structure is processed in the structure analyzer. The structure analyzer will predict a single list of multiplets from the structure. This multiplet list contains the predicted multiplet chemical shift positions, the predicted multiplicities with the predicted coupling constants. It may also contain error estimations on the predicted values for the chemical shift positions and the coupling constants. Then the two multiplet lists are matched in an iterative way where each predicted multiplet is matched to each multiplet resulting from the spectral analysis and the best matches are then counted. It is also possible to perform an overall analysis of all matches, where it might happen that a better overall match is found when the best matches for each single multiplet are not counted.
The known system then will produce a matching score where the overall matching factor and/or the single multiplet matching factors are passed along together with the resulting assignment, whereby the assignment specifies which atom or group in the molecule gave rise to which signal. In this way it is possible to assign a number of atoms to a certain area in the spectrum which then can be used to quantify the concentration of this compound in the solution. In some cases the matching score and the multiplet assignment is passed along to a result simplifier, which then applies a predefined empirical threshold to the matching score and thus decides whether the matching score is good enough to declare the expected molecular structure consistent with the spectrum or not.
However the result will only yield the correct concentration provided an expected structure is given, provided that the expected structure is correct, provided that the prediction of the list of multiples was correct and provided that the multiplet comparator matched the correct predicted multiplet to the correct experimental multiplet.
It is therefore an object of the invention to provide an optimized method and a system for automated analysis of MR-spectra which yields reliable information about concentration of a component of a sample without predicting an expected structure and which yields reliable interpretation of the NMR spectrum when an expected structure is supplied and thus declaring a spectrum consistent or inconsistent with the expected structure in a similar way a human expert would do this.